Besides the usual websites that everyone knows for sharing photos (Facebook, Flickr, Twitter, Picasa), there are some great alternatives out there. This list was put together by Mashable.
SmugMug is a photo sharing website that will interest the avid photographer. It differs from the major photo sharing websites in that it is not free of charge, but it does currently have a free trial available if you are thinking about signing up. If you do decide to sign up, there are three tiers of membership, each offering a different number of features. Some of these features include the ability to password protect selected galleries, add custom watermarks, buy and sell photos and share your own on SNS. SmugMug currently has apps available for iOS and Android.
PicPlz is a free service for sharing and viewing photos. It also has free apps available for both iOS and Android 2.1+. PicPlz allows you to share your photos to Facebook and Twitter and also checks in to Foursquare. It also gives you the ability to apply effects to your photos, browse those of other users and comment on them.
Instagram is the much talked about photo sharing app for the iPhone. Instagram does not have a desktop website, but the app for the iPhone is completely free. You can apply filters to photos that you have taken and then share them on the likes of Twitter, Facebook and Picasa. It’s easy to use interface makes it a popular app for not only sharing your own photos but also browsing those of others.